Sodium chloride is the principal extracellular electrolyte salt, used clinically as an intravenous crystalloid (most commonly 0.9% "normal saline"), oral or parenteral electrolyte replacement, hypertonic solution for symptomatic hyponatremia, nebulized irrigant in cystic fibrosis and bronchiectasis, ophthalmic decongestant, and pharmaceutical diluent[1]. Normal saline (154 mEq/L Na+ and 154 mEq/L Cl-) is the most widely administered medicinal product in the world.
Roughly 20-25% of an IV bolus remains intravascular at 1 hour
Half-life
Not applicable (electrolyte)
Bioavailability
100% (IV); essentially complete (oral)
Pregnancy
Standard fluid and electrolyte management
Legal status
Rx-only for parenteral formulations; OTC for oral, nasal, and many nebulizer products
Purported mechanism
Sodium chloride solutions expand the extracellular volume in proportion to their tonicity; high-volume 0.9% saline reliably produces hyperchloremic metabolic acidosis, which is why balanced crystalloids like Lactated Ringer's are often preferred for large-volume resuscitation.0 Hypertonic 3% is the standard urgent treatment of severely symptomatic hyponatremia[1].
